Window covering parts and apparatus and methods for making the same

ABSTRACT

A hollow, rigid window covering component for use as a slat or otherwise, generally used as an alternative to wood, the component being filled with a foam using a substantially continuous manufacturing process. The apparatus used for this process comprises a die having a substantially toroid-shaped resin chamber and a channel or void through which to inject a core material into the enclosed perimeter of the hollow window covering component.

RELATED APPLICATIONS

This application claims priority to U.S. provisional application Ser. No. 60/570,240, filed May 12, 2004.

BACKGROUND

1. Field of the Invention

The present invention relates generally to coverings for windows or for other similar openings. More particularly, the present invention relates to window covering parts and methods and apparatus for making the same.

2. Background Information

Window coverings such as shutters or blinds are often used to cover windows and other similar openings to provide privacy or to control the level of light that enters a room. A blind, sometimes called a “Venetian” blind, is a popular type of window covering and comprises a series of spaced-apart slats or louvers assembled parallel to each other. In some cases, the slats are disposed horizontally with respect to the window; in others, the slats are disposed vertically.

In recent years, blinds made of wooden slats have gained popular appeal. Since solid wood can be expensive, slats made of various solid wood alternatives have also become popular. Examples of such alternatives include: metal, vinyl, PVC foam, ABS wood composite, plywood, solid thermoplastics, or a combination of any of these. While usually less expensive than solid wood, slats constructed from these wood-alternative materials are inferior to solid wood slats in terms of beam strength. The inferior beam strength, in turn, structurally limits the slat length or span width. In other words, these wood-alternative blinds require more support members (also called ladder supports) in order to span the same window breadth as a wood slat. Consequently, a greater number of ladder supports must necessarily be incorporated into wood-alternative blinds in order to prevent the slats from sagging. This equates to higher materials costs, higher manufacturing costs, and a generally less aesthetically pleasing finished product. Typically, a ladder support must be placed every 10 to 12 inches along the length of a wood-alternative slat, compared to placing ladder supports every 21 to 24 inches for wood slats.

SUMMARY OF THE INVENTION

In a preferred embodiment, the present invention comprises a hollow, rigid window covering part, such as, for example, as slat, filled with a generally less dense material, and apparatus and methods for making the same. The apparatus comprises a die from which hollow window covering parts are extruded. The die comprises a void or channel which provides access to the interior of the hollow widow covering part as it exits the die. The method disclosed comprises adding a material to the interior of the hollow slat through the central void or channel in the die. The resulting combination of an extruded hollow window covering component part filled with a second material provides a slat or other window covering part having greater structural strength (stiffness) than any wood-alternative material having appropriate weight and cost characteristics, and does so via a novel and highly efficient continuous manufacturing process.

In a preferred embodiment of the present invention, a thermoplastic resin is extruded from the die to form the hollow slat and a thermoset foam is introduced into the hollow slat. The thermoset foam reacts with moisture (or with an accompanying chemical agent) as it is introduced into the hollow slat. In another preferred embodiment, a foamed thermoplastic resin is introduced into the hollow slat.

Those skilled in the art will recognize that the thermoset foam, foamed thermoplastic resin, or other suitable material introduced into the hollow slat can easily be adjusted to different densities so as to provide the desired balance of qualities such as structural strength, lightness, insulating ability, materials cost, or others.

Accordingly, it is an object of the present invention to provide a hollow, filled window covering part designed to be incorporated into a wood-alternative window covering.

It is another object of the present invention to provide a strong and stiff but lightweight window covering part that is better than any existing wood-alternative in combined strength and lightness.

It is yet another object of the present invention to provide an alternative material for constructing blinds and other window coverings.

It is a further object of the present invention to provide methods and apparatus for making window covering parts wherein a thermoplastic resin is extruded from a die having a void or channel in order to introduce a second material into a hollow window covering component part.

It is a further object of the present invention to provide sufficiently strong window covering parts comprising a smaller volume of material than is possible using techniques in the prior art for constructing slats and other parts from thermoplastic resins.

It is a still further object of the present invention to provide methods and apparatus that are capable of producing window covering parts at an increased rate.

These and other objects and features of the present invention will be apparent from the detailed description and by reference to accompanying Figures.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other objects and features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a cut-away cross-sectional view of a die used to extrude a window covering component, and through which a core material is introduced, according to a preferred embodiment of the present invention.

FIG. 2 illustrates a front view of the die shown in FIG. 1.

FIG. 3 illustrates the steps used in a preferred embodiment to create a window covering component according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description, in conjunction with the accompanying drawings (hereby expressly incorporated as part of this detailed description), sets forth specific configurations in order to provide a thorough understanding of the present invention. The following detailed description, in conjunction with the drawings, will enable one skilled in the relevant art to make and use the present invention.

A purpose of this detailed description being to describe the invention so as to enable one skilled in the art to make and use the present invention, the following description sets forth various specific examples, also referred to as “embodiments,” of the present invention. While the invention is described in conjunction with specific embodiments, it will be understood, because the embodiments are set forth for explanatory purposes only, that this description is not intended to limit the invention to these particular embodiments. Indeed, it is emphasized that the present invention can be embodied or performed in a variety of ways. The drawings and detailed description are merely representative of particular embodiments of the present invention.

Extruding components used in the construction of window coverings is well known in the art. Extruded components provide a relatively low-cost, easily manufactured alternative to components made from wood or metal. In some cases, these components are hollow, with various shapes of ribbing or structural members disposed within a generally hollow core. Entirely hollow structures may lack structural strength (such as, for example, stiffness), while the use of ribbing to increase stiffness greatly increases the manufacturing complexity of the extrusion process. It can also significantly increase the materials cost of the finished product, as much more material is used to create ribbing than would be needed to create only the shell or outer perimeter of the desired shape.

Accordingly, it is highly desirable in the window coverings industry to have an extruded outer shell that can be constructed using low-cost extrusion techniques, but to introduce into the hollow center of such components some additional material to provide increased structural strength without greatly increasing the weight or materials costs of the finished product.

U.S. Pat. Nos. 6,592,789 and 6,880,588, both issued to Barsby, disclose a method of filling a hollow extruded component with a foam. Barsby's method, however, requires that the window covering component have an opening within its perimeter into which a foam-injection head can be inserted as the long axis of the extruded component passes adjacent to the injection head. Clearly, this requirement of an open perimeter (effectively, a “U” shaped cross-section) detracts from the desirability and flexibility of Barsby's method.

The present invention discloses a novel apparatus and method of introducing material into the fully-enclosed perimeter (having an unbroken cross-section) of a hollow extruded window covering component such as a window blind slat.

FIG. 3 illustrates the steps comprising a preferred embodiment of the present invention. A melted resin 100 is provided. In a preferred embodiment, a thermoplastic resin is used. An appropriate resin may be selected by those skilled in the art based upon the desired cost, rigidity, and other characteristics of the finished window covering component. The resin selected may include, but not be limited to, any of the following: ABS, ASA, PVC, polypropylene, polyethylene, PET, PETG, polycarbonate, and polystyrene. Various composites may be used that include any of these or other resins. Those skilled in the art can select materials having the desired cost, rigidity, and formability characteristics. The melted state of the selected resin can be achieved by any system known in the art. In a preferred embodiment, an extrusion machine (not shown in FIG. 3) is used to melt a pelletized thermoplastic and deliver it in a melted state as melted resin 100 of the present invention.

Die extruder 110 comprises a die 10 having a channel 80 into which melted resin 100 is fed using any technique known in the art. Die 10 further comprises, in a preferred embodiment, a substantially toroid-shaped resin chamber 40 into which the melted resin flows as it is fed or forced into die 10. Die 10 is represented in a cut-away cross-section in FIG. 1, and in a front view in FIG. 2. Melted resin arrives in resin chamber 40 via channel 80, which may be located at any point on die 10 that is able to connect with resin chamber 40.

As additional melted resin 100 is forced into die 10, melted resin 100 is extruded from die 10 at exit aperture 50. Noting the generally toroid shape of resin chamber 40, the resulting extruded material 60 is, in a preferred embodiment, in the form of a cylinder. It will be appreciated, however, that other extruded shapes could easily be created at this point by manufacturing die 10 with a different exit aperture 50, and forming resin chamber 40 in an appropriate shape that includes other key features as herein disclosed.

The hollow extruded component 60 may be formed as a unitary, extruded member as described and illustrated above. Alternatively, component 60 could be formed as two or more separate elements that are then combined by means of an adhesive or otherwise to form a hollow component having a substantially continuous, fully-enclosed perimeter.

The substantially toroid shape of resin chamber 40 permits a hollow channel or void 20 to be manufactured as part of die 10, so that surface 12 forms the inner portion of exit aperture 50 of die 10, but permits access to the hollow portion of extruded material 60.

In a preferred embodiment, a mandrel 30 is inserted into void 20. Mandrel 30 is connected to a delivery device (not shown) capable of delivering a core material 70 into the center of extruded material 60. Alternatively, die 10 could simply include a suitable channel that communicates with the hollow interior of extruded material 60 though which core material 70 may be delivered.

In a preferred embodiment, core material 70 comprises a thermoset foam such as polyurethane. Numerous other thermoset foams, foamed thermoplastic resins, or other suitable foam core materials are encompassed within the scope of the present invention. The core material, in a preferred embodiment, is delivered in a liquid state, and immediately reacts with moisture or an associated chemical curing agent to begin curing into a solid foam. The state of melted resin 100 as it exits die 10 at exit aperture 50 is such that core material 70 does not necessarily react chemically with melted resin 100, but merely fills the hollow space within the extruded material 60.

Referring again to FIGS. 1 and 3, extruded material 60, now filled with core material 70, is fed into calibrator 130 after leaving die extruder 110. Calibrator 130 includes an appropriate mold that forms extruded material 60 into the final shape desired for the finished window covering component. Because extruded material 60 is not fully cooled, and core material 70 is not fully cured, upon entering calibrator 130, the shape of extruded material 60 can be formed by the molds within calibrator 130. Any shape required for a window covering component may be formed in calibrator 130, including, without limitation, cross-sectional shapes such as ovals, airfoils, rectangles, and circles.

Importantly, calibrator 130 is constructed so as to exert a vacuum pressure on the extruded material 60, and to cool it in a controlled manner using a water bath, air cooling, or any other cooling technique known in the art. The combination of vacuum pressure exerted by calibrator 130 and the internal pressure caused by the curing of core material 70 ensures that extruded material 60 presses firmly against the mold within calibrator 130, maintaining a fixed and regular shape as it passes through calibrator 130 until it is sufficiently cooled and cured. In a preferred embodiment using a thermoplastic resin as extruded material 60 and polyurethane foam as core material 70, the forming and cooling process is completed after about five feet of traverse within calibrator 130.

Those skilled in the art will recognize the inherent advantages of the present invention compared to prior art techniques involving insertion of a foam-like piece into a pre-formed, cooled, and cut hollow window coverings component. The prior art techniques are non-continuous, cannot provide significant structural enhancements, and provide relatively little flexibility in the nature of the core material used without additional materials costs or retooling. The present invention provides the advantages of being a continuous manufacturing process, providing, at the user's option, significant enhancement to structural rigidity, and being a flexible process that permits on-the-fly adjustments of core material density without changing materials or tooling.

Those skilled in the art will also appreciate that the nature of core material 70 can be adjusted as needed at the beginning of a manufacturing process, or during a manufacturing process, to achieve the desired characteristics in the finished product. As specific non-limiting examples, if a lightweight product is desired, the density of foam used for core material 70 can be changed by adjusting the ratios of liquid components (resin and hardener) used in a thermosetting foam, or by adjusting the nature or degree of the blowing agent used with a thermoplastic resin that is used as core material 70. Likewise, if one skilled in the art desires that core material 70 provide additional structural strength, similar adjustments can be made to increase the density of core material 70. In this manner, the amount of materials used to construct a given length of a window covering component can very easily be adjusted to suit the cost and market needs of the manufacturer. Indeed, if structural strength (stiffness) is selected as a primary goal for the manufacturing process, the present invention provides the ability to manufacture a window covering slat having greater stiffness compared to its weight than any other wood-alternative presently available.

Once fully formed and cooled within calibrator 130, extruded material 60, filled with core material 70, exits calibrator 130 as finished product 140. Finished product 140 can then be cut to a desired length, a decorative element can be added, or it can be further processed as desired. Decorations may be added to a finished product by means of coloring, painting, embossing, staining, foiling, printing, wrapping, coating, or by any other means known in the art.

It is underscored that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The embodiments described herein should therefore be deemed only as illustrative. 

1. A method of forming a window covering component comprising the steps of Feeding an extrudable material into a die, said die comprising An input channel, A chamber, An exit aperture through which said extrudable material exits said die to form a hollow window covering component having an unbroken cross-sectional perimeter, and Means for accessing the hollow interior of the window covering component; Injecting a core material through said accessing means of said die into the interior of said window covering component in a substantially continuous process as it exits said die.
 2. A method of forming a window covering component comprising the steps of Feeding a melted extrudable material into a die, said die comprising An input channel into which said melted extrudable material is fed, A chamber, said chamber comprising an inner perimeter and an outer perimeter; and An exit aperture through which said melted extrudable material exits said die to form the exterior shell of said window covering component; Inserting a delivery device into the space within said inner perimeter of said die; Injecting a core material into the interior of said shell of said window covering component using said delivery device; Forming said window covering component into a desired shape; and Cooling said window covering component.
 3. The method of claim 2 in which said melted extrudable material is selected from the group consisting of ABS, ASA, PVC, polypropylene, polyethylene, PET, PETG, polycarbonate, polystyrene, and composites includes any of the foregoing.
 4. The method of claim 2 in which said core material is selected from the group consisting of a thermoset plastic, a foamed thermoplastic resin, and composites includes either of the foregoing.
 5. A window covering component comprising A shell and a core, And formed using a process comprising the steps of Obtaining an extrudable material; Feeding said extrudable material into a die, said die comprising An input channel, A resin chamber, said resin chamber comprising an inner perimeter and an outer perimeter; and An exit aperture through which said extrudable material exits said die to form said shell; Inserting a delivery device into the space within said inner perimeter of said die; and Injecting a core material through said delivery device into the interior of said shell to form said core; and Forming said window covering component into a desired shape.
 6. The window covering component of claim 5 in which said extrudable material is selected from the group consisting of ABS, ASA, PVC, polypropylene, polyethylene, PET, PETG, polycarbonate, polystyrene, and composites includes any of the foregoing.
 7. The window covering component of claim 5 in which said core material is selected from the group consisting of a thermoset plastic, a foamed thermoplastic resin, and composites includes either of the foregoing. 